A Plus
by Luna Darkside
Summary: In which Yoshida Ayumi decides that it is a monumental loss that Shinichi, her excellent physics teacher slash former detective, and Kaito, her brilliant chemistry teacher who is very possibly a pyromaniac, are not dating, and sets to work rectifying the problem. /ShinKai & KaiShin, oneshot, highschoolteachers!au, complete/


_Sorry this is a day late - real life got in the way of posting yesterday!_

_Warnings include shounen-ai, grammar mistakes / errors, mentions of physics and chemistry, highschoolteacher!au, the Detective Boys being little shits, etc._

_Hope you enjoy? - Luna_

**A+**

Shinichi was in the middle of explaining magnetic domains to his attentively listening third period class when the fire alarm went off and the sprinklers turned on.

The academic calm immediately dissolved into a frantic upheaval as girls flailed around, trying to crawl under their desks to keep their shirts from getting wet, and boys desperately attempted to salvage their sopping wet notes, to no avail.

At the front of the classroom, Shinichi set down the piece of chalk he was holding and sighed, glancing at the clock hanging over the blackboard. It was only ten thirty. He would never understand how Kaito managed to do it.

Clapping his hands and managing to regain some semblance of order, Shinichi smiled at his class with resignation. He reached up to swipe his wet bangs off his forehead, mentally groaning when they remained stuck in place. "Well. I suppose we're supposed to go out to the field now, aren't we?"

He ignored the class's groans of _this is the sixth time this year _and _when are they going to fire Kuroba-sensei, anyway?_ and started for the door, trying to pull the damp fabric of his sweater away from his neck. The dry cleaning bill was going to be horrendous this month.

* * *

It was probably not a good thing that the moment he caught sight of Shinichi, dripping and shivering and longsuffering as he led his class onto the field, Kaito stopped paying attention to the principal's very loud and unhappy lecture.

There was just _something_, Kaito reflected musingly as Principal Matsumoto waxed lyrical on the importance of not setting labs on fire, letting students handle hydrochloric acid, etc., about the way Shinichi looked when his soaked sweater clung to his skin, the cerulean of the wool deepened to navy. At the back of Kaito's mind, he thoughtfully decided that Shinichi should really be declared the eighth wonder of the world, considering how he somehow managed to look like a romantic painting come to life when the sunlight filtered through the droplets of water caught in his hair.

"– and this is the fifth time since April that you've set off the fire alarm and the sprinkler systems, Kuroba-kun, and even if Kudou-san recommended you for the position, this is _unacceptable_ –" Principal Matsumoto was saying, all fire and brimstone, when Kaito eventually refocused on the conversation.

"It was the sixth time," he cut in as the principal stopped for breath and prepared for another outburst.

The man paused in his tirade, confused. "What?"

"It was the sixth time that I've set off the fire alarm and the sprinklers," Kaito clarified.

As the man's mouth opened, twin spots of furious color appearing on each of his cheeks, Kaito patted him solidly on the shoulder. "I'm really sorry about this, sir, Nishimura-kun got a little overenthusiastic with the dimethyl sulfide. Anyway, I'm going to go check on my class now. Bye."

He ran off as the principal shrieked, "_He shouldn't even have been handling the dimethyl sulfide without your supervision_," after him. Kaito shook his head as he tore across the field toward Shinichi's class. The man really needed to calm down.

Hearing Kaito's footsteps coming towards him, Shinichi turned around to glare, attendance clipboard tucked under one arm. "What was it this time?"

"It was a small incident with some dimethyl sulfide. I already apologized to the principal," Kaito replied offhandedly, panting a little as he slowed to a stop. And not just because of the run. Up close, Shinichi was positively resplendent, water clinging to his eyelashes and his hair curling softly at the nape of his neck.

Abruptly, Kaito had a strange, inexplicable urge to reach out and run his hands through the unruly bits of Shinichi's hair, massage the pale skin along Shinichi's vertebrae, hold Shinichi's face until color flooded his cheeks. It was a mildly creepy thought, but then again, Kaito had been having mildly creepy thoughts about Shinichi for a long, long time, so.

He had met the "retired" (though to be honest, Shinichi was only as retired as a permanent corpse magnet could be) detective, quite accidentally, after a Kid heist a few years ago. Shinichi had attended the heist more for fun that anything else, having lost most of his competitive desire to catch Kaito after he had restored his body, but all the same, Shinichi had immediately recognized Kaito as Kid.

Surprisingly, that had resulted in a lot of shared coffee and the occasional dinner. And when Kaito had decided he needed more of a job than his magic shows (although those did well enough to support him), Shinichi had put in a recommendation for him at Teitan High, where Shinichi had been employed as a physics teacher for a few years. Kaito had a chemistry degree, Shinichi had insisted when Kaito had protested, and he was good at teaching. It would all be fine.

And, because Kaito had been (and still was) absolutely terrible at saying no to Shinichi, that was how Kaito had ended up as a chemistry teacher. Who quickly earned a reputation as a pyromaniac.

He just preferred to let the students learn for themselves, okay.

When Kaito pulled himself from his thoughts, he found that Shinichi was eyeing him cautiously, arms crossed over his chest. "Why do I feel as if you're not sorry at all?"

"I have no idea," Kaito half-sang, and Shinichi sighed. He pulled at the hem of his sweater with some discomfort.

"This sweater is completely ruined," he muttered, mostly to himself, and Kaito grinned at him.

"Would you like me to buy you a new one?" he offered.

Shinichi narrowed his eyes at Kaito, evidently thinking Kaito was joking. When he realized Kaito was serious, his eyebrows shot up his forehead. "Would you really?"

"Of course," Kaito beamed, patting Shinichi on the shoulder. "Anything for you, Kudou." The worst part was that he wasn't even joking. He would probably try to lasso the moon if Shinichi so much as suggested it.

"Well then," Shinichi smirked, and _wow_, there was something about seeing Shinichi smirk like that, while sopping wet and standing in front of four hundred students, that made something thrill dangerously in Kaito's chest. "I hope you're free on Saturday, then?"

"Of course I am," Kaito replied without bothering to think it over. "Just wait and see. I'll buy you the best sweater in Tokyo."

Despite how dorky Kaito sounded, Shinichi was clearly entertained as he leveled Kaito a Look from underneath his eyelashes. "I look forward to it, Kuroba."

Kaito spent the rest of the day humming to himself as he flitted around lab tables, barely managing to prevent two more fires. He couldn't bring himself to feel the slightest bit chagrined when the principal, who had huffily decided to sit in on the rest of Kaito's lessons for the day, yelled at him after each incident.

* * *

Somehow, Yoshida Ayumi thought as she scribbled down several lines of notes, there was something different about Kudou-sensei today.

And it wasn't just the pretty new sweater he was wearing, Ayumi thought dryly as Shinichi absently brushed chalk dust off the blue fabric, though he certainly seemed to be happy about it. There was something in the way he kept smiling at the class, the way his cheeks were the slightest bit pink, the way his eyes seemed clearer than usual as he elaborated on flux capacitors. There was definitely _something_.

Ayumi tapped her pen against her notebook thoughtfully. This certainly deserved some investigation.

She brought it up with her best friend, Haibara Ai, during lunchtime, as they sat on the rooftop, tucked beside the stairwell to avoid the wind.

"Don't you think Kudou-sensei is acting strange?" she insisted around a mouthful of rice, setting her chopsticks down for maximum flailing. "He was all smiley and happy and blushy! Didn't you see?"

Haibara, unsurprisingly, remained unimpressed as ever, scooping curry out of her bento without even looking at her. "I guess," she mumbled after a pause. "It doesn't really matter to me."

"You're no help at all," Ayumi scowled – why did she even put up with her, _seriously_ – before slumping and going back to her lunch. She glared at the floor, petulantly spearing a piece of rolled egg.

After a long moment, during which Ayumi sulkily chewed and Haibara swallowed noiselessly, Haibara remarked carefully, "Well, if I had to say someone was acting odd today, I would say I noticed Kuroba-sensei more."

"What?" Ayumi stopped viciously prying apart a hot dog octopus to blink at her. "What about Kuroba-sensei?"

"He was strangely enthusiastic," replied Haibara with a shrug. "He set Kojima-kun's homework on fire and the principal got angry, but Kuroba-sensei just stood there and whistled 'Somewhere Over the Rainbow' the entire time he was being yelled at. Usually he actually bothers to try to look sorry, but not today."

Ayumi frowned, staring down into the remains of her lunch. That was suspicious, wasn't it? Come to think of it, weren't Kaito and Shinichi really close? At that evacuation last week, they had certainly seemed like they were. They had stood pretty close to each other… and laughed together… And neither of them were married, were they…?

"Oh my God!" Ayumi clapped so loudly that Haibara actually bothered to shoot her a questioningly look, which she returned with a wide grin. "They're totally in love with each other!"

Haibara just blinked at her.

"No, I swear! It's totally there, Ai-chan, I can see it," she insisted, and Haibara shrugged one shoulder.

"I don't see how it's any of our business what those two do."

Ayumi shook her head at her. Seriously, she didn't know why she bothered with such an obtuse person. "Clearly," she began imperiously, "we have to set them up." The thought made her sigh and clasp her hands to her chest. "We'll be warriors of love. Can you imagine that?"

"No," Haibara answered immediately.

"You have no faith," Ayumi chided, and returned to her lunch with much eagerness.

* * *

They ended up recruiting Kojima Genta, who constantly needed help in chemistry, and Tsuburaya Mitsuhiko, Shinichi's favorite student, because Haibara firmly refused to actively participate and they really needed more than just Ayumi trying to set up Shinichi and Kaito.

The four of them formed a plan at Ayumi's house after school on Tuesday. Well, Ayumi and Mitsuhiko came up with a plan while Haibara and Genta gave each other _how did I end up here _looks over the boxes of pocky that Ayumi had graciously provided.

On Wednesday, they set the plan into motion.

"Kuroba-sensei," Genta called as fourth period let out, "can I talk to you for just a second?"

Kaito, who was in the middle of trying to clean up a gigantic acid spill before the principal walked in for his daily check, nodded absently. "Yes, yes, of course, Kojima-kun. Go ahead."

"Are you, by any chance, dating Kudou-sensei?" Genta tried his hardest to sound casual, though it didn't seem to matter. Kaito was busy with the spill, trying to neutralize it before it dripped onto the floor.

"What? Kudou?" He swore under his breath as the door to the classroom slid open and the principal stalked in, already incensed. "Dating Kudou? I wish."

"Oh, okay. Thanks," Genta quickly told him and ran before the principal launched into a tirade that could be heard for miles around.

Mitsuhiko was in charge of the second part of the plan, which was much more complicated due to the fact that Shinichi was rarely caught off guard and wasn't likely to be easily distracted.

"Kudou-sensei!" Mitsuhiko chirped after sixth period, practically flying to the front of the classroom to corner Shinichi at his desk. Shinichi, who was shuffling around a few stray test papers and twirling a red pen, blinked up at him.

"Yes, Tsuburaya-kun?" he asked, setting the pen down to devote his full attention to Mitsuhiko.

"I have some problems that I need help with." Without waiting for Shinichi's response, Mitsuhiko pulled a sheet of paper covered in advanced quantum mechanics problems out of his shoulder bag and slapped them down in front of him. "Can you help me?"

"Of course." Shinichi blinked down at the paper, eyes narrowed as he scrambled to grab a pencil. "Just a question, though – why, exactly, do you need help with wavefunction probability currents, Tsuburaya-kun?"

"It's for, uh, a… project," Mitsuhiko stammered in response, sweating a little. Technically it wasn't a lie. And Shinichi looked too engrossed in working out the problem to pay much attention to him.

Once Shinichi started on the fifth problem, eyebrows furrowed as he provided commentary on the intricacies of wave-particle duality and the Schrodinger equation (commentary that probably would've been helpful had Mitsuhiko actually been interested in the problems), Mitsuhiko asked, nonchalantly, "Are you dating anyone, Kudou-sensei?"

"– and here you have to solve for – what? Dating?" Shinichi barely looked up from the paper, penciling in a few diagrams beside problem five. "No, I'm not dating anyone right now. As you can see, this variable is usually –"

"Are you interested in anyone?"

"– the easiest to substitute – hm? Interested in someone?" Shinichi actually put down the pencil to blink at Mitsuhiko. "What's with all these questions?"

Flinching, Mitsuhiko shrank away from Shinichi's inquisitive expression. "It's – nothing." He tried to smile. "Problem six?"

"Oh, this one's easy. It's just the photoelectric equation – look, here you have to…"

Mitsuhiko let him ramble on for another minute or two. Once Shinichi was thoroughly absorbed in explaining the Planck constant, he asked, "Would you date Kuroba-sensei, if he asked?"

"– in Joules per second, the constant is equal to approximately – what? Date Kuroba? Of course I would," Shinichi responded, clearly without thinking, because half a second later he froze and turned a blank gaze on Mitsuhiko.

"Tsuburaya-kun," he said, voice disturbingly emotionless.

Sensing that Shinichi was not entirely pleased with him, Mitsuhiko let out a squeak – it was a well-warranted squeak, in his opinion; he'd heard that Shinichi solved murders in his spare time, and didn't that mean he knew how to kill people without getting caught? – and snatched the paper off Shinichi's desk.

"Thank you, Kudou-sensei," he managed before bolting.

Upon hearing the results of both parts of the plan, Ayumi practically cackled, to Haibara's concerned amusement.

Step three, then.

* * *

Frowning down at the note in his hand, Shinichi pushed open the door to the chemistry lab and took a few steps in. "Kuroba?" he called, glancing around the room. The setting sun pouring through the uncovered windows illuminated the black-topped lab stations and the rows of desks, but no Kaito.

Shinichi peered down at the piece of paper he was still holding. In typed letters, it read, _Kudou – could you meet me at the chem lab around five tonight? Thanks. – Kuroba_. This had been suspicious enough, because Shinichi couldn't imagine Kaito ever bothering to type something when he could just force Shinichi to read his awful handwriting, but all the same, Shinichi had decided to come to the class. He'd never forgive himself if it really did turn out to be from Kaito.

He was about to give up leave when Kaito's voice came from behind him. "Kudou? Did you leave me this note?"

Turning, Shinichi was just in time to see Kaito approaching him, holding a piece of paper that Shinichi most certainly did not remember leaving anywhere, right before he caught sight of Yoshida – pretty, sweet, terrible-at-physics-but-overall-nice Yoshida Ayumi – smiling maniacally as she threw something into the classroom and slammed the door shut. There was the sound of metal scraping metal and then footsteps pattering off, accompanied by mildly concerning laughter.

"She padlocked the door shut," Kaito informed Shinichi. He was blinking very quickly.

Shinichi stared.

"It's one of those high security ones," Kaito added, helpfully.

"…Okay." Shinichi ran a hand through his hair. "Well." In an attempt to distract himself, he glanced around the room.

Which turned out to be a mistake, because his gaze landed on the objects Yoshida had thrown into the room. Specifically, the four boxes and three bottles that Yoshida had thrown.

Shinichi must've made some kind of sound, because Kaito followed his line of sight questioningly. His eyebrows shot up in realization. Maybe it was just because of the fading sunset still spilling through the windows, but Shinichi thought he looked a little flushed.

"Oh," Kaito coughed. "Er."

"Right." Shinichi watched, feeling helpless, as Kaito bent to pick up a few of the boxes gingerly. He winced as he read the words "ultra-thin lubricated" and, more disturbingly, "intensely ribbed for maximum pleasure" along the sides of the boxes. "Does she think, um, that it's possible to use all of these in a single, um… night?"

Kaito shrugged, picking up one of the bottles. "I don't know, but she has good taste in lube." He coughed. "And I mean that literally. This is chocolate-covered strawberry flavored." He peered down at another one bottle. "And this one's piña colada. The last one is plain. Probably in case we don't like her flavor choices."

Scowling, Shinichi leaned heavily against one of the lab tables. "I don't… why would she do this?" He thought back within the last few days. He had talked about changes in flux, and then Tsuburaya had approached him with those problems, and then –

_Wait_. Shinichi blinked. Tsuburaya had asked some strange questions, right, about whether he was in a relationship or if he would date Kaito –

"This does _not _count as dating," Shinichi groaned aloud before he could stop himself.

"What?" Kaito glanced up from his examination of the lube bottles. "What doesn't count as dating?"

Shaking his head, Shinichi sighed loudly. "A few days ago, Tsuburaya-kun – you have him for chemistry too, don't you? – approached me and asked if I would date you. I mean, I said yes, but I wasn't expecting _this _to happen. This doesn't even constitute as a date. We're literally locked in your classroom together with four boxes of condoms and three bottles of lube. It's not exactly romantic, especially knowing…?"

It took Shinichi a moment to realize that Kaito wasn't paying attention to his rant at all. Instead, he was gaping at Shinichi with lips parted and eyes wide. The bottle of chocolate-covered strawberry lube dropped from his hand, hitting the ground with a dull crash.

"Kuroba?" Shinichi tried, suddenly feeling nervous as Kaito carefully nudged aside the boxes and advanced on him. He edged backwards until the back of his knees hit a desk, feeling his heart banging against his ribcage frantically.

But Kaito didn't moving until he was pressed up against Shinichi, close enough that Shinichi could count his eyelashes. He was having difficulty breathing – understandably, in Shinichi's opinion, because he could feel the jut of Kaito's hipbones against his, smell the remnants of citrusy cologne Kaito liked to use sometimes.

"Did you just say you would date me?" Kaito murmured. Shinichi couldn't help but marvel at how the fading light from the sunset caught in the tips of Kaito's hair, illuminated his skin, set his eyes on fire.

Shinichi opened his mouth, prepared to make some sarcastic comment, but all that came out was a quiet, "Yes," and then Kaito's lips were on his and everything else ceased to exist.

* * *

The next morning, Ayumi was unhappy to find out that "someone" had kicked out the door to the chemistry lab during the night. She had paid a _lot _for that padlock.

She entered her physics class with some dejection, tossing her books at her desk listlessly as she settled in. Great. She'd tried _so hard _to get Shinichi and Kaito together, but in the end, they'd just been too stubborn.

Pulling her notebook out of her bag, Ayumi began to flip towards her most recent notes when someone cleared their throat. Blinking, she looked up to find Shinichi standing over her desk, eyeing her pointedly.

"Kudou-sensei!" she fairly squeaked, pushing her chair backwards.

"Yoshida-san," he replied sternly. "Don't think that I didn't recognize you last night. What you did yesterday was very wrong. What if Kuroba-sensei had started a fire in the classroom and we couldn't escape? Granted, we were able to kick the door down, but it was a possibility." He raised his eyebrows. "Also, you implied something very suggestive with what you left behind."

Ayumi wilted, embarrassed. At the time, it had seemed like a good idea, but now just she felt terrible. She had probably humiliated both of her favorite teachers, and just because she'd thought – she'd _thought _–

"I expect that your behavior will improve and that nothing like this will ever happen again," Shinichi concluded, frowning down at Ayumi's frantic nodding, and began to head to the front of the classroom to start the lecture.

But not before he cast one last glance at her over his shoulder – and Ayumi started, because was he _smiling_? – and whispered, "The chocolate-covered strawberry flavor was my favorite."

Mouth falling open, Ayumi gawped in abject astonishment as Shinichi practically sashayed (there was no other way to describe the way he was walking) to the blackboard and began writing equations.

Her mouth was still open ten minutes later, when the fire alarm and sprinkler system went off.

* * *

**GOODBYE. *flies away in shame***

**Anyway. Um. If you enjoyed this fic even a little bit, please consider leaving me a review, and I'll see you all later! - Luna**


End file.
